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Leng X, Wang H, Cao L, Chang R, Zhang S, Xu C, Yu J, Xu X, Qu C, Xu Z, Liu G. Overexpressing GLUTAMINE SYNTHETASE 1;2 maintains carbon and nitrogen balance under high-ammonium conditions and results in increased tolerance to ammonium toxicity in hybrid poplar. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:4052-4073. [PMID: 38497908 DOI: 10.1093/jxb/erae124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 03/16/2024] [Indexed: 03/19/2024]
Abstract
The glutamine synthetase/glutamic acid synthetase (GS/GOGAT) cycle plays important roles in N metabolism, growth, development, and stress resistance in plants. Excess ammonium (NH4+) restricts growth, but GS can help to alleviate its toxicity. In this study, the 84K model clone of hybrid poplar (Populus alba × P. tremula var. glandulosa), which has reduced biomass accumulation and leaf chlorosis under high-NH4+ stress, showed less severe symptoms in transgenic lines overexpressing GLUTAMINE SYNTHETASE 1;2 (GS1;2-OE), and more severe symptoms in RNAi lines (GS1;2-RNAi). Compared with the wild type, the GS1;2-OE lines had increased GS and GOGAT activities and higher contents of free amino acids, soluble proteins, total N, and chlorophyll under high-NH4+ stress, whilst the antioxidant and NH4+ assimilation capacities of the GS1;2-RNAi lines were decreased. The total C content and C/N ratio in roots and leaves of the overexpression lines were higher under stress, and there were increased contents of various amino acids and sugar alcohols, and reduced contents of carbohydrates in the roots. Under high-NH4+ stress, genes related to amino acid biosynthesis, sucrose and starch degradation, galactose metabolism, and the antioxidant system were significantly up-regulated in the roots of the overexpression lines. Thus, overexpression of GS1;2 affected the carbon and amino acid metabolism pathways under high-NH4+ stress to help maintain the balance between C and N metabolism and alleviate the symptoms of toxicity. Modification of the GS/GOGAT cycle by genetic engineering is therefore a potential strategy for improving the NH4+ tolerance of cultivated trees.
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Affiliation(s)
- Xue Leng
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
- College of Agriculture, Jilin Agricultural Science and Technology University, Jilin 132109, China
| | - Hanzeng Wang
- College of Agriculture, Jilin Agricultural Science and Technology University, Jilin 132109, China
| | - Lina Cao
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
| | - Ruhui Chang
- College of Life Science, Northeast Forestry University, Harbin 150040, China
| | - Shuang Zhang
- College of Life Science, Northeast Forestry University, Harbin 150040, China
| | - Caifeng Xu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
| | - Jiajie Yu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
| | - Xiuyue Xu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
| | - Chunpu Qu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
- College of Forestry, Guizhou University, Guiyang 550025, China
| | - Zhiru Xu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
- College of Life Science, Northeast Forestry University, Harbin 150040, China
| | - Guanjun Liu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
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Li X, Gu Y, Kayoumu M, Muhammad N, Wang X, Gui H, Luo T, Wang Q, Wumaierjiang X, Ruan S, Iqbal A, Zhang X, Song M, Dong Q. Systematic characterization of Gossypium GLN family genes reveals a potential function of GhGLN1.1a regulates nitrogen use efficiency in cotton. BMC PLANT BIOLOGY 2024; 24:313. [PMID: 38654158 PMCID: PMC11036627 DOI: 10.1186/s12870-024-04990-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 04/05/2024] [Indexed: 04/25/2024]
Abstract
The enzyme glutamine synthetase (GLN) is mainly responsible for the assimilation and reassimilation of nitrogen (N) in higher plants. Although the GLN gene has been identified in various plants, there is little information about the GLN family in cotton (Gossypium spp.). To elucidate the roles of GLN genes in cotton, we systematically investigated and characterized the GLN gene family across four cotton species (G. raimondii, G. arboreum, G. hirsutum, and G. barbadense). Our analysis encompassed analysis of members, gene structure, cis-element, intragenomic duplication, and exploration of collinear relationships. Gene duplication analysis indicated that segmental duplication was the primary driving force for the expansion of the GhGLN gene family. Transcriptomic and quantitative real-time reverse-transcription PCR (qRT-PCR) analyses indicated that the GhGLN1.1a gene is responsive to N induction treatment and several abiotic stresses. The results of virus-induced gene silencing revealed that the accumulation and N use efficiency (NUE) of cotton were affected by the inactivation of GhGLN1.1a. This study comprehensively analyzed the GhGLN genes in Gossypium spp., and provides a new perspective on the functional roles of GhGLN1.1a in regulating NUE in cotton.
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Affiliation(s)
- Xiaotong Li
- Zhengzhou Research Base, National Key Laboratory of Cotton Bio-Breeding and Integrated Utilization, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, Henan, China
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Yunqi Gu
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Mirezhatijiang Kayoumu
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Noor Muhammad
- Zhengzhou Research Base, National Key Laboratory of Cotton Bio-Breeding and Integrated Utilization, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, Henan, China
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Xiangru Wang
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Huiping Gui
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Tong Luo
- Western Agricultural Research Center of Chinese Academy of Agricultural Sciences, Changji, 831100, Xinjiang, China
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Qianqian Wang
- Western Agricultural Research Center of Chinese Academy of Agricultural Sciences, Changji, 831100, Xinjiang, China
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Xieraili Wumaierjiang
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Sijia Ruan
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Asif Iqbal
- Department of Agriculture, Hazara University, Khyber Pakhtunkhwa, Mansehra, 21120, Pakistan
| | - Xiling Zhang
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China
| | - Meizhen Song
- Zhengzhou Research Base, National Key Laboratory of Cotton Bio-Breeding and Integrated Utilization, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, Henan, China.
- Western Agricultural Research Center of Chinese Academy of Agricultural Sciences, Changji, 831100, Xinjiang, China.
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China.
| | - Qiang Dong
- Western Agricultural Research Center of Chinese Academy of Agricultural Sciences, Changji, 831100, Xinjiang, China.
- National Engineering Research Center of Cotton Biology Breeding and Industrial Technology /Institute of Cotton Research of CAAS, Anyang, 455000, Henan, China.
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Fortunato S, Nigro D, Lasorella C, Marcotuli I, Gadaleta A, de Pinto MC. The Role of Glutamine Synthetase (GS) and Glutamate Synthase (GOGAT) in the Improvement of Nitrogen Use Efficiency in Cereals. Biomolecules 2023; 13:1771. [PMID: 38136642 PMCID: PMC10742212 DOI: 10.3390/biom13121771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
Cereals are the most broadly produced crops and represent the primary source of food worldwide. Nitrogen (N) is a critical mineral nutrient for plant growth and high yield, and the quality of cereal crops greatly depends on a suitable N supply. In the last decades, a massive use of N fertilizers has been achieved in the desire to have high yields of cereal crops, leading to damaging effects for the environment, ecosystems, and human health. To ensure agricultural sustainability and the required food source, many attempts have been made towards developing cereal crops with a more effective nitrogen use efficiency (NUE). NUE depends on N uptake, utilization, and lastly, combining the capability to assimilate N into carbon skeletons and remobilize the N assimilated. The glutamine synthetase (GS)/glutamate synthase (GOGAT) cycle represents a crucial metabolic step of N assimilation, regulating crop yield. In this review, the physiological and genetic studies on GS and GOGAT of the main cereal crops will be examined, giving emphasis on their implications in NUE.
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Affiliation(s)
- Stefania Fortunato
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (S.F.)
| | - Domenica Nigro
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.N.); (I.M.)
| | - Cecilia Lasorella
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (S.F.)
| | - Ilaria Marcotuli
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.N.); (I.M.)
| | - Agata Gadaleta
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.N.); (I.M.)
| | - Maria Concetta de Pinto
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (S.F.)
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Mondal R, Kumar A, Chattopadhyay SK. Structural property, molecular regulation, and functional diversity of glutamine synthetase in higher plants: a data-mining bioinformatics approach. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:1565-1584. [PMID: 34628690 DOI: 10.1111/tpj.15536] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/24/2021] [Accepted: 10/01/2021] [Indexed: 05/26/2023]
Abstract
Glutamine synthetase (GS; E.C.6.3.1.2) is a key enzyme in higher plants with two isozymes, cytosolic GS1 and plastidic GS2, and involves in the assimilation and recycling of NH4+ ions and maintenance of complex traits such as crop nitrogen-use efficiency and yield. Our present understanding of crop nitrogen-use efficiency and its correlation with the functional role of the GS family genes is inadequate, which delays harnessing the benefit of this key enzyme in crop improvement. In this report, we performed a comprehensive investigation on the phylogenetic relationship, structural properties, complex multilevel gene regulation, and expression patterns of the GS genes to enrich present understanding about the enzyme. Our Gene Ontology and protein-protein interactions analysis revealed the functional aspects of GS isozymes in stress mitigation, aging, nucleotide biosynthesis/transport, DNA repair and response to metals. The insight gained here contributes to the future research strategies in developing climate-smart crops for global sustainability.
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Affiliation(s)
- Raju Mondal
- Mulberry Tissue Culture Lab, Central Sericultural Germplasm Resources Centre (CSGRC), Central Silk Board, Ministry of Textile, Govt. of India, Hosur, 635109, India
| | - Amit Kumar
- Host Plant Section, Central Muga Eri Research & Training Institute, Central Silk Board, Ministry of Textile, Govt. of India, Lahdoigarh, Jorhat, Assam, 785700, India
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Wani SH, Vijayan R, Choudhary M, Kumar A, Zaid A, Singh V, Kumar P, Yasin JK. Nitrogen use efficiency (NUE): elucidated mechanisms, mapped genes and gene networks in maize ( Zea mays L.). PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2021; 27:2875-2891. [PMID: 35035142 PMCID: PMC8720126 DOI: 10.1007/s12298-021-01113-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/22/2021] [Accepted: 12/07/2021] [Indexed: 05/22/2023]
Abstract
UNLABELLED Nitrogen, the vital primary plant growth nutrient at deficit soil conditions, drastically affects the growth and yield of a crop. Over the years, excess use of inorganic nitrogenous fertilizers resulted in pollution, eutrophication and thereby demanding the reduction in the use of chemical fertilizers. Being a C4 plant with fibrous root system and high NUE, maize can be deployed to be the best candidate for better N uptake and utilization in nitrogen deficient soils. The maize germplasm sources has enormous genetic variation for better nitrogen uptake contributing traits. Adoption of single cross maize hybrids as well as inherent property of high NUE has helped maize cultivars to achieve the highest growth rate among the cereals during last decade. Further, considering the high cost of nitrogenous fertilizers, adverse effects on soil health and environmental impact, maize improvement demands better utilization of existing genetic variation for NUE via introgression of novel allelic combinations in existing cultivars. Marker assisted breeding efforts need to be supplemented with introgression of genes/QTLs related to NUE in ruling varieties and thereby enhancing the overall productivity of maize in a sustainable manner. To achieve this, we need mapped genes and network of interacting genes and proteins to be elucidated. Identified genes may be used in screening ideal maize genotypes in terms of better physiological functionality exhibiting high NUE. Future genome editing may help in developing lines with increased productivity under low N conditions in an environment of optimum agronomic practices. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s12298-021-01113-z.
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Affiliation(s)
- Shabir H. Wani
- Genetics and Plant Breeding, Mountain Research Centre For Field Crops, Sher-E-Kashmir University of Agricultural Sciences and Technology of Kashmir, Khudwani Anantnag, J&K 192101 India
| | - Roshni Vijayan
- Regional Agricultural Research Station-Central Zone, Kerala Agricultural University, MelePattambi, Palakkad, Kerala 679306 India
| | | | - Anuj Kumar
- Centre for Agricultural Bioinformatics (CABin), ICAR-Indian Agricultural Statistics Research Institute, New Delhi, 110012 India
| | - Abbu Zaid
- Plant Physiology and Biochemistry Section, Department of Botany, Aligarh Muslim University, Aligarh, 202002 India
| | - Vishal Singh
- Department of Plants, Soils and Climate, Utah State University, 4820 Old Main Hill, Logan, UT 84322 USA
| | - Pardeep Kumar
- ICAR-Indian Institute of Maize Research, Ludhiana, 141001 India
| | - Jeshima Khan Yasin
- Division of Genomic Resources, ICAR-National Bureau Plant Genetic Resources, PUSA Campus, New Delhi, 110012 India
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Wen B, Luo Y, Liu D, Zhang X, Peng Z, Wang K, Li J, Huang J, Liu Z. The R2R3-MYB transcription factor CsMYB73 negatively regulates l-Theanine biosynthesis in tea plants (Camellia sinensis L.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 298:110546. [PMID: 32771159 DOI: 10.1016/j.plantsci.2020.110546] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/08/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
l-Theanine, a non-proteinaceous amino acid abundantly present in tea (Camellia sinensis), contributes to the umami flavor of tea and has beneficial effects on human health. While key l-theanine biosynthetic genes have been well documented, their transcriptional regulation remains poorly understood. In this study, we determined the l-theanine contents in tea leaves of two cultivars at three developmental stages and investigated the expression patterns of the l-theanine biosynthetic genes CsGS1 and CsGS2. Additionally, we identified an R2R3-MYB transcription factor, CsMYB73, belonging to subgroup 22 of the R2R3-MYB family. CsMYB73 expression negatively correlated with l-theanine accumulation during leaf maturation. We found that CsMYB73, as a nuclear protein, binds to the promoter regions of CsGS1 and CsGS2 via MYB recognition sequences and represses the transcription of CsGS1 and CsGS2 in tobacco leaves. Collectively, our results demonstrate that CsMYB73 is a transcriptional repressor involved in l-theanine biosynthesis in tea plants. Our findings might contribute to future tea plant breeding strategies.
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Affiliation(s)
- Beibei Wen
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, PR China
| | - Yong Luo
- School of Chemistry, Biology and Environmental Engineering, Xiangnan University, Chenzhou, Hunan 423000, PR China
| | - Dongmin Liu
- Changsha University of Science & Technology, Changsha, Hunan 410114, PR China
| | - Xiangna Zhang
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, PR China
| | - Zhong Peng
- National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients & Hunan Co-innovation Center for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, PR China
| | - Kunbo Wang
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, PR China; National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients & Hunan Co-innovation Center for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, PR China.
| | - Juan Li
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, PR China; National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients & Hunan Co-innovation Center for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, PR China
| | - Jianan Huang
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, PR China; National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients & Hunan Co-innovation Center for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, PR China.
| | - Zhonghua Liu
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, PR China; National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients & Hunan Co-innovation Center for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, PR China.
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Abstract
Nitrogen (N) is a macro-nutrient that is essential for growth development and resistance against biotic and abiotic stresses of plants. Nitrogen is a constituent of amino acids, proteins, nucleic acids, chlorophyll, and various primary and secondary metabolites. The atmosphere contains huge amounts of nitrogen but it cannot be taken up directly by plants. Plants can take up nitrogen in the form of nitrate, ammonium, urea, nitrite, or a combination of all these forms. In addition, in various leguminous rhizobia, bacteria can convert atmospheric nitrogen to ammonia and supply it to the plants. The form of nitrogen nutrition is also important in plant growth and resistance against pathogens. Nitrogen content has an important function in crop yield. Nitrogen deficiency can cause reduced root growth, change in root architecture, reduced plant biomass, and reduced photosynthesis. Hence, understanding the function and regulation of N metabolism is important. Several enzymes and intermediates are involved in nitrogen assimilation. Here we provide an overview of the important enzymes such as nitrate reductase, nitrite reductase, glutamine synthase, GOGAT, glutamate dehydrogenase, and alanine aminotransferase that are involved in nitrogen metabolism.
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Dechorgnat J, Francis KL, Dhugga KS, Rafalski JA, Tyerman SD, Kaiser BN. Root Ideotype Influences Nitrogen Transport and Assimilation in Maize. FRONTIERS IN PLANT SCIENCE 2018; 9:531. [PMID: 29740466 PMCID: PMC5928562 DOI: 10.3389/fpls.2018.00531] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 04/05/2018] [Indexed: 05/02/2023]
Abstract
Maize (Zea mays, L.) yield is strongly influenced by external nitrogen inputs and their availability in the soil solution. Overuse of nitrogen-fertilizers can have detrimental ecological consequences through increased nitrogen pollution of water and the release of the potent greenhouse gas, nitrous oxide. To improve yield and overall nitrogen use efficiency (NUE), a deeper understanding of nitrogen uptake and utilization is required. This study examines the performance of two contrasting maize inbred lines, B73 and F44. F44 was selected in Florida on predominantly sandy acidic soils subject to nitrate leaching while B73 was selected in Iowa on rich mollisol soils. Transcriptional, enzymatic and nitrogen transport analytical tools were used to identify differences in their N absorption and utilization capabilities. Our results show that B73 and F44 differ significantly in their genetic, enzymatic, and biochemical root nitrogen transport and assimilatory pathways. The phenotypes show a strong genetic relationship linked to nitrogen form, where B73 showed a greater capacity for ammonium transport and assimilation whereas F44 preferred nitrate. The contrasting phenotypes are typified by differences in root system architecture (RSA) developed in the presence of both nitrate and ammonium. F44 crown roots were longer, had a higher surface area and volume with a greater lateral root number and density than B73. In contrast, B73 roots (primary, seminal, and crown) were more abundant but lacked the defining features of the F44 crown roots. An F1 hybrid between B73 and F44 mirrored the B73 nitrogen specificity and root architecture phenotypes, indicating complete dominance of the B73 inbred. This study highlights the important link between RSA and nitrogen management and why both variables need to be tested together when defining NUE improvements in any selection program.
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Affiliation(s)
- Julie Dechorgnat
- Sydney Institute of Agriculture, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia
| | - Karen L. Francis
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA, Australia
| | | | - J. A. Rafalski
- Genetic Discovery Group, DuPont Crop Genetics Research, DuPont Experimental Station, Wilmington, DE, United States
| | - Stephen D. Tyerman
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA, Australia
| | - Brent N. Kaiser
- Sydney Institute of Agriculture, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia
- *Correspondence: Brent N. Kaiser,
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Cheng S, Fu X, Wang X, Liao Y, Zeng L, Dong F, Yang Z. Studies on the Biochemical Formation Pathway of the Amino Acid l-Theanine in Tea (Camellia sinensis) and Other Plants. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:7210-7216. [PMID: 28796499 DOI: 10.1021/acs.jafc.7b02437] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Tea (Camellia sinensis) is the most widely consumed beverage aside from water. The flavor of tea is conferred by certain metabolites, especially l-theanine, in C. sinensis. To determine why more l-theanine accumulates in C. sinensis than in other plants, we compare l-theanine contents between C. sinensis and other plant species (Camellia nitidissima, Camellia japonica, Zea mays, Arabidopsis thaliana, and Solanum lycopersicum) and use a stable isotope labeling approach to elucidate its biosynthetic route. We quantify relevant intermediates and metabolites by mass spectrometry. l-Glutamic acid, a precursor of l-theanine, is present in most plants, while ethylamine, another precursor of l-theanine, specifically accumulates in Camellia species, especially C. sinensis. Most plants contain the enzyme/gene catalyzing the conversion of ethylamine and l-glutamic acid to l-theanine. After supplementation with [2H5]ethylamine, all the plants produce [2H5]l-theanine, which suggests that ethylamine availability is the reason for the difference in l-theanine accumulation between C. sinensis and other plants.
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Affiliation(s)
- Sihua Cheng
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences , Xingke Road 723, Tianhe District, Guangzhou 510650, China
- University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing 100049, China
| | - Xiumin Fu
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences , Xingke Road 723, Tianhe District, Guangzhou 510650, China
| | - Xiaoqin Wang
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences , Xingke Road 723, Tianhe District, Guangzhou 510650, China
- University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing 100049, China
| | - Yinyin Liao
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences , Xingke Road 723, Tianhe District, Guangzhou 510650, China
| | - Lanting Zeng
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences , Xingke Road 723, Tianhe District, Guangzhou 510650, China
- University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing 100049, China
| | - Fang Dong
- Guangdong Food and Drug Vocational College , Longdongbei Road 321, Tianhe District, Guangzhou 510520, China
| | - Ziyin Yang
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences , Xingke Road 723, Tianhe District, Guangzhou 510650, China
- University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing 100049, China
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Zhang Z, Xiong S, Wei Y, Meng X, Wang X, Ma X. The role of glutamine synthetase isozymes in enhancing nitrogen use efficiency of N-efficient winter wheat. Sci Rep 2017; 7:1000. [PMID: 28428629 PMCID: PMC5430530 DOI: 10.1038/s41598-017-01071-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/27/2017] [Indexed: 11/26/2022] Open
Abstract
Glutamine synthetase (GS) isozymes play critical roles in nitrogen (N) metabolism. However, the exact relationship between GS and nitrogen use efficiency (NUE) remain unclear. We have selected and compared two wheat cultivars, YM49 and XN509, which were identified as the N-efficient and N-inefficient genotypes, respectively. In this study, agronomical, morphological, physiological and biochemical approaches were performed. The results showed that TaGS1 was high expressed post-anthesis, and TaGS2 was highly expressed pre-anthesis in N-efficient genotype compared to N-inefficient genotype. GS1 and GS2 isozymes were also separated by native-PAGE and found that the spatial and temporal distribution of GS isozymes, their expression of gene and protein subunits in source-sink-flow organs during development periods triggered the pool strength and influenced the N flow. According to the physiological role of GS isozymes, we illustrated four metabolic regulation points, by which acting collaboratively in different organs, accelerating the transport of nutrients to the grain. It suggested that the regulation of GS isozymes may promote flow strength and enhance NUE by a complex C-N metabolic mechanism. The relative activity or amount of GS1 and GS2 isozymes could be a potential marker to predict and select wheat genotypes with enhanced NUE.
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Affiliation(s)
- Zhiyong Zhang
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, 450002, China
- College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
- Key Laboratory of Physiology, Ecology and Genetic Improvement of Food Crops in HenanProvince, Zhengzhou, 450002, China
| | - Shuping Xiong
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, 450002, China
- College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
- Key Laboratory of Physiology, Ecology and Genetic Improvement of Food Crops in HenanProvince, Zhengzhou, 450002, China
| | - Yihao Wei
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, 450002, China
- College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
- Key Laboratory of Physiology, Ecology and Genetic Improvement of Food Crops in HenanProvince, Zhengzhou, 450002, China
| | - Xiaodan Meng
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, 450002, China
- College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
- Key Laboratory of Physiology, Ecology and Genetic Improvement of Food Crops in HenanProvince, Zhengzhou, 450002, China
| | - Xiaochun Wang
- Department of Biochemistry, College of Life Science, Henan Agriculture University, Zhengzhou, 450002, China.
| | - Xinming Ma
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, 450002, China.
- College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China.
- Key Laboratory of Physiology, Ecology and Genetic Improvement of Food Crops in HenanProvince, Zhengzhou, 450002, China.
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11
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Król A, Weidner S. Changes in the proteome of grapevine leaves (Vitis vinifera L.) during long-term drought stress. JOURNAL OF PLANT PHYSIOLOGY 2017; 211:114-126. [PMID: 28178572 DOI: 10.1016/j.jplph.2016.11.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 05/21/2023]
Abstract
The essence of exploring and understanding mechanisms of plant adaptation to environmental stresses lies in the determination of patterns of the expression of proteins, identification of stress proteins and their association with the specific functions in metabolic pathways. To date, little information has been provided about the proteomic response of grapevine to the persistent influence of adverse environmental conditions. This article describes changes in the profile of protein accumulation in leaves of common grapevine (Vitis vinifera L.) seedlings in response to prolonged drought. Isolated proteins were separated by two-dimensional electrophoresis (2 DE), and the proteins whose level of accumulation changed significantly due to the applied stress factors were identified with tandem mass spectrometry MALDI TOF/TOF type. Analysis of the proteome of grapevine leaves led to the detection of many proteins whose synthesis changed in response to the applied stressor. Drought caused the most numerous changes in the accumulation of proteins associated with carbohydrate and energy metabolism, mostly connected with the pathways of glycolysis and photosystem II protein components. The biological function of the identified proteins is discussed with reference to the stress of drought. Some of the identified proteins, especially the ones whose accumulation increased during drought stress, may be responsible for the adaptation of grapevine to drought.
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Affiliation(s)
- Angelika Król
- Department of Biology and Biotechnology, Chair of Biochemistry, University of Warmia and Mazury in Olsztyn, M. Oczapowskiego St. 1A, 10-957 Olsztyn, Kortowo, Poland.
| | - Stanisław Weidner
- Department of Biology and Biotechnology, Chair of Biochemistry, University of Warmia and Mazury in Olsztyn, M. Oczapowskiego St. 1A, 10-957 Olsztyn, Kortowo, Poland
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12
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Yang C, Zhang L, Jia A, Rong T. Identification of QTL for maize grain yield and kernel-related traits. J Genet 2017; 95:239-47. [PMID: 27350665 DOI: 10.1007/s12041-016-0628-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Grain yield (GY) is one of the most important and complex quantitative traits in maize (Zea mays L.) breeding practice. Quantitative trait loci (QTLs) for GY and three kernel-related traits were detected in a set of recombinant inbred lines (RILs). One hundred and seven simple sequence repeats (SSRs) and 168 insertion/deletion polymorphism markers (Indels) were used to genotype RILs. Eight QTLs were found to be associated with four yield-related traits: GY, 100-kernel weight (HKW), 10-kernel length (KL), and 10-kernel length width (KW). Each QTL explained between 5.96 (qKL2-1) and 13.05 (qKL1-1) per cent of the phenotypic variance. Notably, one common QTL, located at the marker interval between bnlg1893 and chr2- 236477 (chromosomal bin 2.09) simultaneously controlled GY and HKW; another common QTL, at bin 2.03 was simultaneously responsible for HKW and KW. Of the QTLs identified, only one pair of significant epistatic interaction involved in chromosomal region at bin 2.03 was detected for HKW; no significant QTL × environment interactions were observed. These results provide the common QTLs and for marker-assisted breeding.
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Affiliation(s)
- Cong Yang
- Maize Research, Sichuan Agricultural University, Wenjiang 611130, Sichuan, People's Republic of
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Goron TL, Raizada MN. Biosensor-based spatial and developmental mapping of maize leaf glutamine at vein-level resolution in response to different nitrogen rates and uptake/assimilation durations. BMC PLANT BIOLOGY 2016; 16:230. [PMID: 27769186 PMCID: PMC5075184 DOI: 10.1186/s12870-016-0918-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 10/10/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND The amino acid glutamine (Gln) is a primary transport form of nitrogen in vasculature following root uptake, critical for the location/timing of growth in maize and other cereals. Analytical chemistry methods do not permit in situ analysis of Gln, including visualization within the vascular network. Their cost and tissue requirement are barriers to exploring the complexity of Gln dynamics. We previously reported a biosensor, GlnLux, which can measure relative Gln levels inexpensively with tiny amounts of tissue. RESULTS Here, maize seedlings were given different N rates for multiple uptake/assimilation durations, after which > 1500 leaf disk extracts were analyzed. A second technique permitted in situ imaging of Gln for all leaves sampled simultaneously. We demonstrate that multifactorial interactions govern Gln accumulation involving position within each leaf (mediolateral/proximodistal), location of leaves along the shoot axis, N rate, and uptake duration. In situ imaging localized Gln in leaf veins for the first time. A novel hypothesis is that leaf Gln may flow along preferential vascular routes, for example in response to mechanical damage or metabolic needs. CONCLUSIONS The GlnLux technology enabled the most detailed map of relative Gln accumulation in any plant, and the first report of in situ Gln at vein-level resolution. The technology might be used with any plant species in a similar manner.
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Affiliation(s)
- Travis L. Goron
- Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1 Canada
| | - Manish N. Raizada
- Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1 Canada
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14
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Daghino S, Martino E, Perotto S. Model systems to unravel the molecular mechanisms of heavy metal tolerance in the ericoid mycorrhizal symbiosis. MYCORRHIZA 2016; 26:263-274. [PMID: 26710764 DOI: 10.1007/s00572-015-0675-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/16/2015] [Indexed: 06/05/2023]
Abstract
Ericoid mycorrhizal plants dominate in harsh environments where nutrient-poor, acidic soil conditions result in a higher availability of potentially toxic metals. Although metal-tolerant plant species and ecotypes are known in the Ericaceae, metal tolerance in these plants has been mainly attributed to their association with ericoid mycorrhizal fungi. The mechanisms underlying plant protection by the fungal symbiont are poorly understood, whereas some insights have been achieved regarding the molecular mechanisms of heavy metal tolerance in the fungal symbiont. This review will briefly introduce the general features of heavy metal tolerance in mycorrhizal fungi and will then focus on the use of "omics" approaches and heterologous expression in model organisms to reveal the molecular bases of fungal response to heavy metals. Functional complementation in Saccharomyces cerevisiae has allowed the identification of several ericoid mycorrhizal fungi genes (i.e., antioxidant enzymes, metal transporters, and DNA damage repair proteins) that may contribute to metal tolerance in a metal-tolerant ericoid Oidiodendron maius isolate. Although a powerful system, the use of the yeast complementation assay to study metal tolerance in mycorrhizal symbioses has limitations. Thus, O. maius has been developed as a model system to study heavy metal tolerance mechanisms in mycorrhizal fungi, thanks to its high metal tolerance, easy handling and in vitro mycorrhization, stable genetic transformation, genomics, transcriptomic and proteomic resources.
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Affiliation(s)
- Stefania Daghino
- Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125, Turin, Italy
| | - Elena Martino
- Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125, Turin, Italy
| | - Silvia Perotto
- Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125, Turin, Italy.
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15
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Wang X, Wei Y, Shi L, Ma X, Theg SM. New isoforms and assembly of glutamine synthetase in the leaf of wheat (Triticum aestivum L.). JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6827-34. [PMID: 26307137 PMCID: PMC4623691 DOI: 10.1093/jxb/erv388] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Glutamine synthetase (GS; EC 6.3.1.2) plays a crucial role in the assimilation and re-assimilation of ammonia derived from a wide variety of metabolic processes during plant growth and development. Here, three developmentally regulated isoforms of GS holoenzyme in the leaf of wheat (Triticum aestivum L.) seedlings are described using native-PAGE with a transferase activity assay. The isoforms showed different mobilities in gels, with GSII>GSIII>GSI. The cytosolic GSI was composed of three subunits, GS1, GSr1, and GSr2, with the same molecular weight (39.2kDa), but different pI values. GSI appeared at leaf emergence and was active throughout the leaf lifespan. GSII and GSIII, both located in the chloroplast, were each composed of a single 42.1kDa subunit with different pI values. GSII was active mainly in green leaves, while GSIII showed brief but higher activity in green leaves grown under field conditions. LC-MS/MS experiments revealed that GSII and GSIII have the same amino acid sequence, but GSII has more modification sites. With a modified blue native electrophoresis (BNE) technique and in-gel catalytic activity analysis, only two GS isoforms were observed: one cytosolic and one chloroplastic. Mass calibrations on BNE gels showed that the cytosolic GS1 holoenzyme was ~490kDa and likely a dodecamer, and the chloroplastic GS2 holoenzyme was ~240kDa and likely a hexamer. Our experimental data suggest that the activity of GS isoforms in wheat is regulated by subcellular localization, assembly, and modification to achieve their roles during plant development.
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Affiliation(s)
- Xiaochun Wang
- Collaborative Innovation Center of Henan Grain Crops, Henan Agriculture University, Zhengzhou 450002, China State Key Laboratory of Wheat and Maize Crop Science in China, Henan Agriculture University, Zhengzhou 450002, China Department of Biochemistry, College of Life Science, Henan Agriculture University, Zhengzhou 450002, China
| | - Yihao Wei
- Department of Biochemistry, College of Life Science, Henan Agriculture University, Zhengzhou 450002, China
| | - Lanxin Shi
- Department of Plant Biology, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Xinming Ma
- Collaborative Innovation Center of Henan Grain Crops, Henan Agriculture University, Zhengzhou 450002, China
| | - Steven M Theg
- Department of Plant Biology, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
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Prinsi B, Espen L. Mineral nitrogen sources differently affect root glutamine synthetase isoforms and amino acid balance among organs in maize. BMC PLANT BIOLOGY 2015; 15:96. [PMID: 25886826 PMCID: PMC4393875 DOI: 10.1186/s12870-015-0482-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/24/2015] [Indexed: 05/03/2023]
Abstract
BACKGROUND Glutamine synthetase (GS) catalyzes the first step of nitrogen assimilation in plant cell. The main GS are classified as cytosolic GS1 and plastidial GS2, of which the functionality is variable according to the nitrogen sources, organs and developmental stages. In maize (Zea mays L.) one gene for GS2 and five genes for GS1 subunits are known, but their roles in root metabolism are not yet well defined. In this work, proteomic and biochemical approaches have been used to study root GS enzymes and nitrogen assimilation in maize plants re-supplied with nitrate, ammonium or both. RESULTS The plant metabolic status highlighted the relevance of root system in maize nitrogen assimilation during both nitrate and ammonium nutrition. The analysis of root proteomes allowed a study to be made of the accumulation and phosphorylation of six GS proteins. Three forms of GS2 were identified, among which only the phosphorylated one showed an accumulation trend consistent with plastidial GS activity. Nitrogen availabilities enabled increments in root total GS synthetase activity, associated with different GS1 isoforms according to the nitrogen sources. Nitrate nutrition induced the specific accumulation of GS1-5 while ammonium led to up-accumulation of both GS1-1 and GS1-5, highlighting co-participation. Moreover, the changes in thermal sensitivity of root GS transferase activity suggested differential rearrangements of the native enzyme. The amino acid accumulation and composition in roots, xylem sap and leaves deeply changed in response to mineral sources. Glutamine showed the prevalent changes in all nitrogen nutritions. Besides, the ammonium nutrition was associated with an accumulation of asparagine and reducing sugars and a drop in glutamic acid level, significantly alleviated by the co-provision with nitrate. CONCLUSION This work provides new information about the multifaceted regulation of the GS enzyme in maize roots, indicating the involvement of specific isoenzymes/isoforms, post-translational events and biochemical factors. For the first time, the proteomic approach allowed to discriminate the individual contribution of the GS1 isoforms, highlighting the participation of GS1-5 in nitrate metabolism. Moreover, the results give new insights about the influence of amino acid metabolism in plant C/N balance.
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Affiliation(s)
- Bhakti Prinsi
- Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia (DISAA), Università degli Studi di Milano, Via Celoria, 2, 20133, Milano, Italy.
| | - Luca Espen
- Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia (DISAA), Università degli Studi di Milano, Via Celoria, 2, 20133, Milano, Italy.
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Zanin L, Zamboni A, Monte R, Tomasi N, Varanini Z, Cesco S, Pinton R. Transcriptomic Analysis Highlights Reciprocal Interactions of Urea and Nitrate for Nitrogen Acquisition by Maize Roots. ACTA ACUST UNITED AC 2014; 56:532-48. [DOI: 10.1093/pcp/pcu202] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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18
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Khouja H, Daghino S, Abbà S, Boutaraa F, Chalot M, Blaudez D, Martino E, Perotto S. OmGOGAT-disruption in the ericoid mycorrhizal fungus Oidiodendron maius induces reorganization of the N pathway and reduces tolerance to heavy-metals. Fungal Genet Biol 2014; 71:1-8. [DOI: 10.1016/j.fgb.2014.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/01/2014] [Accepted: 08/07/2014] [Indexed: 10/24/2022]
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19
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Bao A, Zhao Z, Ding G, Shi L, Xu F, Cai H. Accumulated expression level of cytosolic glutamine synthetase 1 gene (OsGS1;1 or OsGS1;2) alter plant development and the carbon-nitrogen metabolic status in rice. PLoS One 2014; 9:e95581. [PMID: 24743556 PMCID: PMC3990726 DOI: 10.1371/journal.pone.0095581] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 03/28/2014] [Indexed: 11/19/2022] Open
Abstract
Maintaining an appropriate balance of carbon to nitrogen metabolism is essential for rice growth and yield. Glutamine synthetase is a key enzyme for ammonium assimilation. In this study, we systematically analyzed the growth phenotype, carbon-nitrogen metabolic status and gene expression profiles in GS1;1-, GS1;2-overexpressing rice and wildtype plants. Our results revealed that the GS1;1-, GS1;2-overexpressing plants exhibited a poor plant growth phenotype and yield and decreased carbon/nitrogen ratio in the stem caused by the accumulation of nitrogen in the stem. In addition, the leaf SPAD value and photosynthetic parameters, soluble proteins and carbohydrates varied greatly in the GS1;1-, GS1;2-overexpressing plants. Furthermore, metabolite profile and gene expression analysis demonstrated significant changes in individual sugars, organic acids and free amino acids, and gene expression patterns in GS1;1-, GS1;2-overexpressing plants, which also indicated the distinct roles that these two GS1 genes played in rice nitrogen metabolism, particularly when sufficient nitrogen was applied in the environment. Thus, the unbalanced carbon-nitrogen metabolic status and poor ability of nitrogen transportation from stem to leaf in GS1;1-, GS1;2-overexpressing plants may explain the poor growth and yield.
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Affiliation(s)
- Aili Bao
- Microelement Research Center, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Zhuqing Zhao
- Microelement Research Center, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Guangda Ding
- Microelement Research Center, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Lei Shi
- Microelement Research Center, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Fangsen Xu
- Microelement Research Center, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Hongmei Cai
- Microelement Research Center, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
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Zhu C, Fan Q, Wang W, Shen C, Meng X, Tang Y, Mei B, Xu Z, Song R. Characterization of a glutamine synthetase gene DvGS2 from Dunaliella viridis and biochemical identification of DvGS2-transgenic Arabidopsis thaliana. Gene 2014; 536:407-15. [PMID: 24334123 DOI: 10.1016/j.gene.2013.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/16/2013] [Accepted: 11/05/2013] [Indexed: 01/23/2023]
Abstract
The salt-tolerant green alga Dunaliella has remarkable capability to survive in some extreme environments such as nitrogen starvation, which makes Dunaliella be a proper model for mining novel genes on nitrogen uptake or assimilation. In this study, a glutamine synthetase (GS) gene DvGS2 with amino acid identity of 72% to other homologous GS proteins, was isolated and characterized from Dunaliella viridis. Phylogenetic comparison with other GSs revealed that DvGS2 occupied an independent phylogenetic position. Expressional analysis in D. viridis cells under nitrogen starvation confirmed that DvGS2 increased its mRNA level in 12h. Subcellular localization study and functional analysis in a GS-deficient Escherichia coli mutant proved that DvGS2 was a chloroplastic and functional GS enzyme. In order to investigate the potential application of DvGS2 in higher plants, the transgenic studies of DvGS2 in Arabidopsis thaliana were carried out. Results showed that the transgenic lines expressed the DvGS2 gene and demonstrated obviously enhanced root length (29%), fresh weight (40%-48% at two concentrations of nitrate supplies), stem length (21%), leaf size (39%) and silique number (44%) in contrast with the wild-type Arabidopsis. Furthermore, the transgenic lines had higher total nitrogen content (35%-43%), total GS activity (39%-45%) and soluble protein concentration (23%-24%) than the wild type. These results indicated that the overexpression of DvGS2 in A. thaliana resulted in higher biomass and the improvement of the host's nitrogen use efficiency.
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Affiliation(s)
- Chenguang Zhu
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
| | - Qianlan Fan
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
| | - Wei Wang
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
| | - Chunlei Shen
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
| | - Xiangzong Meng
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
| | - Yuanping Tang
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
| | - Bing Mei
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
| | - Zhengkai Xu
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China
| | - Rentao Song
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, 200444 Shanghai, China.
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Zhu C, Fan Q, Wang W, Shen C, Wang P, Meng X, Tang Y, Mei B, Xu Z, Song R. Characterization of a glutamine synthetase gene DvGS1 from Dunaliella viridis and investigation of the impact on expression of DvGS1 in transgenic Arabidopsis thaliana. Mol Biol Rep 2013; 41:477-87. [PMID: 24307252 DOI: 10.1007/s11033-013-2882-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 11/21/2013] [Indexed: 11/26/2022]
Abstract
A novel glutamine synthetase (GS) gene DvGS1 showing highest amino acid sequence identity of 78 % with the other homologous GS proteins from green algae, was isolated and characterized from Dunaliella viridis. Phylogenetic analysis revealed that DvGS1 occupied an independent phylogenetic position which was different with the GSs from higher plants, animals and microbes. Functional complement in E. coli mutant confirmed that the DvGS1 encoded functional GS enzyme. Real-time PCR analysis of DvGS1 in D. viridis cells under nitrogen starvation revealed that the mRNA level of DvGS1 was positively up-regulated in 12 h. The DvGS1 levels at the points of 12 and 24 h were separately twofold and fourfold of the level before nitrogen starvation. In order to investigate the potential application of DvGS1 in higher plants, the transgenic study of DvGS1 in Arabidopsis thaliana was carried out. Phenotype identification demonstrated that all three transgenic lines of T3 generation showed obviously enhanced root length (26 %), fresh weight (22-46 % at two concentrations of nitrate supplies), stem length (26 %), leaf size (29 %) and silique number (30 %) compared with the wild-type Arabidopsis. Biochemical analysis confirmed that all three transgenic lines had higher total nitrogen content, soluble protein concentration, total amino acid content and the leaf GS activity than the wild type plants. The free NH4 (+) and NO3 (-) concentration in fresh leaves of three transgenic lines were reduced by 17-26 % and 14-15 % separately (at two concentrations of nitrate supplies) compared with those of the wild types. All the results indicated that over-expression of DvGS1 in Arabidopsis significantly results in the improvement of growth phenotype and the host's nitrogen use efficiency.
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Affiliation(s)
- Chenguang Zhu
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
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Seabra AR, Silva LS, Carvalho HG. Novel aspects of glutamine synthetase (GS) regulation revealed by a detailed expression analysis of the entire GS gene family of Medicago truncatula under different physiological conditions. BMC PLANT BIOLOGY 2013; 13:137. [PMID: 24053168 PMCID: PMC3848809 DOI: 10.1186/1471-2229-13-137] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 09/16/2013] [Indexed: 05/20/2023]
Abstract
BACKGROUND Glutamine Synthetase (GS, EC 6.3.1.2) is a central enzyme in nitrogen metabolism, and a key component of nitrogen use efficiency (NUE) and plant yield and thus it is extremely important to understand how it is regulated in plants. Medicago truncatula provides an excellent model system to study GS, as it contain a very simple GS gene family comprising only four expressed genes, MtGS1a and MtGS1b encoding cytosolic polypeptides, and MtGS2a and MtGS2b encoding plastid-located enzymes. To identify new regulatory mechanisms controlling GS activity, we performed a detailed expression analysis of the entire GS gene family of M. truncatula in the major organs of the plant, over a time course of nodule or seed development and during a diurnal cycle. RESULTS Individual GS transcripts were quantified by qRT-PCR, and GS polypeptides and holoenzymes were evaluated by western blot and in-gel activity under native electrophoresis. These studies revealed that all four GS genes are differentially regulated in each organ of the plant, in a developmental manner, and identified new regulatory controls, which appear to be specific to certain metabolic contexts. Studies of the protein profiles showed that the GS polypeptides assemble into organ-specific protein complexes and suffer organ-specific post-translational modifications under defined physiological conditions. Our studies also reveal that GS expression and activity are modulated during a diurnal cycle. The biochemical properties of the four isoenzymes were determined and are discussed in relation to their function in the plant. CONCLUSIONS This work provides a comprehensive overview of GS expression and regulation in the model legume M. truncatula, contributing to a better understanding of the specific function of individual isoenzymes and to the identification of novel organ-specific post-translational mechanisms of GS regulation. We demonstrate that the GS proteins are modified and/or integrated into protein-complexes that assemble into a specific composition in particular organs of the plant. Taken together, the results presented here open new avenues to explore the regulatory mechanisms controlling GS activity in plants, a subject of major importance due to the crucial importance of the enzyme for plant growth and productivity.
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Affiliation(s)
- Ana R Seabra
- Instituto de Biologia Molecular e Celular da Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
- Current address: Max Planck Group for Fungal Biodiversity, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Köln, Germany
| | - Liliana S Silva
- Instituto de Biologia Molecular e Celular da Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Helena G Carvalho
- Instituto de Biologia Molecular e Celular da Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
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Lothier J, Gaufichon L, Sormani R, Lemaître T, Azzopardi M, Morin H, Chardon F, Reisdorf-Cren M, Avice JC, Masclaux-Daubresse C. The cytosolic glutamine synthetase GLN1;2 plays a role in the control of plant growth and ammonium homeostasis in Arabidopsis rosettes when nitrate supply is not limiting. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:1375-90. [PMID: 20959627 DOI: 10.1093/jxb/erq299] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Glutamine synthetase (EC 6.3.1.2) is a key enzyme of ammonium assimilation and recycling in plants where it catalyses the synthesis of glutamine from ammonium and glutamate. In Arabidopsis, five GLN1 genes encode GS1 isoforms. GLN1;2 is the most highly expressed in leaves and is over-expressed in roots by ammonium supply and in rosettes by ample nitrate supply compared with limiting nitrate supply. It is shown here that the GLN1;2 promoter is mainly active in the minor veins of leaves and flowers and, to a lower extent, in the parenchyma of mature leaves. Cytoimmunochemistry reveals that the GLN1;2 protein is present in the companion cells. The role of GLN1;2 was determined by examining the physiology of gln1;2 knockout mutants. Mutants displayed lower glutamine synthetase activity, higher ammonium concentration, and reduced rosette biomass compared with the wild type (WT) under ample nitrate supply only. No difference between mutant and WT can be detected under limiting nitrate conditions. Despite total amino acid concentration was increased in the old leaves of mutants at high nitrate, no significant difference in nitrogen remobilization can be detected using (15)N tracing. Growing plants in vitro with ammonium or nitrate as the sole nitrogen source allowed us to confirm that GLN1;2 is induced by ammonium in roots and to observe that gln1;2 mutants displayed, under such conditions, longer root hair and smaller rosette phenotypes in ammonium. Altogether the results suggest that GLN1;2 is essential for nitrogen assimilation under ample nitrate supply and for ammonium detoxification.
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Affiliation(s)
- Jérémy Lothier
- Institut Jean-Pierre Bourgin (IJPB) UMR 1318, INRA, F-78026 Versailles Cedex, France
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Seabra AR, Vieira CP, Cullimore JV, Carvalho HG. Medicago truncatula contains a second gene encoding a plastid located glutamine synthetase exclusively expressed in developing seeds. BMC PLANT BIOLOGY 2010; 10:183. [PMID: 20723225 PMCID: PMC3095313 DOI: 10.1186/1471-2229-10-183] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Accepted: 08/19/2010] [Indexed: 05/20/2023]
Abstract
BACKGROUND Nitrogen is a crucial nutrient that is both essential and rate limiting for plant growth and seed production. Glutamine synthetase (GS), occupies a central position in nitrogen assimilation and recycling, justifying the extensive number of studies that have been dedicated to this enzyme from several plant sources. All plants species studied to date have been reported as containing a single, nuclear gene encoding a plastid located GS isoenzyme per haploid genome. This study reports the existence of a second nuclear gene encoding a plastid located GS in Medicago truncatula. RESULTS This study characterizes a new, second gene encoding a plastid located glutamine synthetase (GS2) in M. truncatula. The gene encodes a functional GS isoenzyme with unique kinetic properties, which is exclusively expressed in developing seeds. Based on molecular data and the assumption of a molecular clock, it is estimated that the gene arose from a duplication event that occurred about 10 My ago, after legume speciation and that duplicated sequences are also present in closely related species of the Vicioide subclade. Expression analysis by RT-PCR and western blot indicate that the gene is exclusively expressed in developing seeds and its expression is related to seed filling, suggesting a specific function of the enzyme associated to legume seed metabolism. Interestingly, the gene was found to be subjected to alternative splicing over the first intron, leading to the formation of two transcripts with similar open reading frames but varying 5' UTR lengths, due to retention of the first intron. To our knowledge, this is the first report of alternative splicing on a plant GS gene. CONCLUSIONS This study shows that Medicago truncatula contains an additional GS gene encoding a plastid located isoenzyme, which is functional and exclusively expressed during seed development. Legumes produce protein-rich seeds requiring high amounts of nitrogen, we postulate that this gene duplication represents a functional innovation of plastid located GS related to storage protein accumulation exclusive to legume seed metabolism.
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Affiliation(s)
- Ana R Seabra
- Instituto de Biologia Molecular e Celular da Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Cristina P Vieira
- Instituto de Biologia Molecular e Celular da Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Julie V Cullimore
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de la Recherche Agronomique - Centre National de la Recherche Scientifique, Boite Postale 52627, 31326 Castanet-Tolosan Cedex, France
| | - Helena G Carvalho
- Instituto de Biologia Molecular e Celular da Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
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Sun F, Yang X, Li Y, Hou X. Molecular cloning and characterisation of cytoplasmic glutamine synthetase gene BcGS1 from non-heading Chinese cabbage. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2010; 90:891-897. [PMID: 20355127 DOI: 10.1002/jsfa.3900] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
BACKGROUND Glutamine synthetase (GS; EC 6.3.1.2) is a key enzyme of nitrogen (N) assimilation, catalysing the synthesis of glutamine from ammonium and glutamate. Plants have two types of GS isoenzyme that are localised in different compartments: one in the cytosol (GS1) and the other in the chloroplast (GS2). GS1 is the major form of GS in plant roots and directly converts ammonium taken up by plant roots to glutamine. RESULTS The GS1 gene cDNA of non-heading Chinese cabbage (Brassica campestrisssp. chinensis Makino) cultivar 'Suzhouqing' was isolated by RT-PCR (real-time polymerase chain reaction) and (5'/3')-RACE (rapid amplification of cDNA ends) techniques. It was classified as GS1 by sequence alignment and motif search and named B. campestris ssp. chinensis Makino GS1 (BcGS1). Subcellular localisation analysis showed that BcGS1 was distributed in the cytoplasm of cells. BcGS1 was expressed in all parts, but mainly in the roots, which was verified by northern blotting analysis. Additionally, its expression was influenced by the N source concentration. CONCLUSION These results suggest that BcGS1 is a novel member of the GS family in plants. BcGS1 was significantly related to N assimilation in non-heading Chinese cabbage, demonstrating that this gene plays an important role in plant growth and development.
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Affiliation(s)
- Feifei Sun
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
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Broyart C, Fontaine JX, Molinié R, Cailleu D, Tercé-Laforgue T, Dubois F, Hirel B, Mesnard F. Metabolic profiling of maize mutants deficient for two glutamine synthetase isoenzymes using 1H-NMR-based metabolomics. PHYTOCHEMICAL ANALYSIS : PCA 2010; 21:102-9. [PMID: 19866455 DOI: 10.1002/pca.1177] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
INTRODUCTION Maize mutants deficient for the expression of two genes encoding cytosolic glutamine synthetase (GS) isoenzymes GS1.3 and GS1.4 displayed reduced kernel number and kernel size, respectively, the effect of the mutation being cumulative in the double mutant. However, at maturity, shoot biomass production was not modified in all the mutants, indicating that the reaction catalysed by the enzyme is specifically involved in the control of grain yield. OBJECTIVE To examine the physiological impact of the GS mutations on the leaf metabolic profile during the kernel filling period, during which nitrogen is remobilized from the shoots to be further exported to the kernels. METHODOLOGY An (1)H-NMR spectroscopy metabolomic was applied to the investigation of metabolic change of the gln1.3, gln1.4 and gln1.3/1.4 double mutant. RESULTS In the three GS mutants, an increase in the amount of several N-containing metabolites such as asparagine, alanine, threonine and phophatidylcholine was observed whatever the level of nitrogen fertilisation. In addition, we found an accumulation of phenylalanine and tyrosine, two metabolites involved the primary steps of the phenylpropanoid pathway. CONCLUSION Changes in the metabolic profile of the GS mutants suggest that, when cytosolic GS activity is strongly reduced, either alternative metabolic pathways participate in the reassimilation of ammonium released during leaf protein remobilization or that premature leaf senescence is induced when kernel set and kernel filling are affected. The accumulation of phenylalanine and tyrosine in the mutant plants indicates that lignin biosynthesis is altered, thus possibly affecting ear development.
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Affiliation(s)
- Caroline Broyart
- EA 3900-BioPI Biologie des Plantes et Contrôle des Insectes Ravageurs, Faculté de Pharmacie, 1, rue des Louvels et Faculté des Sciences, 33, rue Saint Leu, 80037 Amiens cedex 1, France
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Occhipinti A, Berlicki Ł, Giberti S, Dziedzioła G, Kafarski P, Forlani G. Effectiveness and mode of action of phosphonate inhibitors of plant glutamine synthetase. PEST MANAGEMENT SCIENCE 2010; 66:51-58. [PMID: 19697446 DOI: 10.1002/ps.1830] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
BACKGROUND Aiming at the rational design of new herbicides, the availability of the three-dimensional structure of the target enzyme greatly enhances the optimisation of lead compounds and the design of derivatives with increased activity. Among the most widely exploited herbicide targets is glutamine synthetase. Recently, the structure of a cytosolic form of the maize enzyme has been described, making it possible to verify whether steric, electronic and hydrophobic features of a compound are in agreement with inhibitor-protein interaction geometry. RESULTS Three series of compounds (aminophosphonates, hydroxyphosphonates and aminomethylenebisphosphonates) were evaluated as possible inhibitors of maize glutamine synthetase. Aminomethylenebisphosphonate derivatives substituted in the phenyl ring retained the inhibitory potential, whereas variations in the scaffold, i.e. the replacement of the second phosphonate moiety with a hydroxyl or an amino residue, resulted in a significant loss of activity. A kinetic characterisation showed a non-competitive mechanism against glutamate and an uncompetitive mechanism against ATP. A docking analysis suggested the mode of bisphosphonate binding to the active site. CONCLUSION Results made it possible to define the features required to maintain or enhance the biological activity of these compounds, which represent lead structures to be further exploited for the design of new substances endowed with herbicidal activity.
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Affiliation(s)
- Andrea Occhipinti
- Department of Biology and Evolution, University of Ferrara, Ferrara, Italy
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Seabra AR, Carvalho H, Pereira PJB. Crystallization and preliminary crystallographic characterization of glutamine synthetase from Medicago truncatula. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:1309-12. [PMID: 20054137 PMCID: PMC2802889 DOI: 10.1107/s1744309109047381] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 11/09/2009] [Indexed: 11/11/2022]
Abstract
The condensation of ammonium and glutamate into glutamine catalyzed by glutamine synthetase (GS) is a fundamental step in nitrogen metabolism in all kingdoms of life. In plants, this is preceded by the reduction of inorganic nitrogen to an ammonium ion and therefore effectively articulates nitrogen fixation and metabolism. Although the three-dimensional structure of the dodecameric bacterial GS was determined quite some time ago, the quaternary architecture of the plant enzyme has long been assumed to be octameric, mostly on the basis of low-resolution electron-microscopy studies. Recently, the crystallographic structure of a monocotyledonous plant GS was reported that revealed a homodecameric organization. In order to unambiguously establish the quaternary architecture of GS from dicotyledonous plants, GS1a from the model legume Medicago truncatula was overexpressed, purified and crystallized. The collection of synchrotron diffraction data to 2.35 A resolution allowed the determination of the three-dimensional structure of this enzyme by molecular replacement.
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Affiliation(s)
- Ana Rita Seabra
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal
| | - Helena Carvalho
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal
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Nord-Larsen PH, Kichey T, Jahn TP, Jensen CS, Nielsen KK, Hegelund JN, Schjoerring JK. Cloning, characterization and expression analysis of tonoplast intrinsic proteins and glutamine synthetase in ryegrass (Lolium perenne L.). PLANT CELL REPORTS 2009; 28:1549-1562. [PMID: 19655146 DOI: 10.1007/s00299-009-0754-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 07/20/2009] [Accepted: 07/20/2009] [Indexed: 05/28/2023]
Abstract
Perennial ryegrass (Lolium perenne L.) is the most important turf and forage grass species of the temperate regions. It requires substantial input of nitrogen fertilizer for optimum yield. Improved nitrogen use efficiency (NUE) is therefore one of the main breeding targets. However, limited knowledge is currently available on the genes controlling NUE in perennial ryegrass. The aim of the present study was to isolate genes involved in ammonium transport and assimilation. In silico screening of a Lolium EST-library using known sequences of tonoplast intrinsic proteins (TIPs) and cytosolic glutamine synthetase (GS1) revealed a number of homologous sequences. Using these sequences, primers were designed to obtain the full-length sequences by RACE-PCR. Three TIP genes (LpTIP1;1, LpTIP1;2 and LpTIP2;1) and two GS genes (LpGS1a and LpGS1b) were isolated. Characterization in S. cerevisiae confirmed a function in ammonium transport for LpTIP1;1 and LpTIP2;1 and in synthesis of glutamine for LpGS1a and LpGS1b. Cytoimmunochemical studies showed that GS protein was present in the chloroplasts and cytosol of leaf cells, while TIP1 proteins localized to the tonoplast. At the expression level, Lolium GS1 genes responded to N starvation and re-supply in a manner consistent with functions in primary N assimilation and N remobilization. Similarly, the expression of LpTIPs complied with a role in vacuolar ammonium storage. Together, the reported results provide new understanding of the genetic basis for N assimilation and storage in ryegrass.
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Affiliation(s)
- Pia H Nord-Larsen
- Plant and Soil Science Laboratory, Department of Agriculture and Ecology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark
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Prinsi B, Negri AS, Pesaresi P, Cocucci M, Espen L. Evaluation of protein pattern changes in roots and leaves of Zea mays plants in response to nitrate availability by two-dimensional gel electrophoresis analysis. BMC PLANT BIOLOGY 2009; 9:113. [PMID: 19698183 PMCID: PMC2744680 DOI: 10.1186/1471-2229-9-113] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 08/23/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND Nitrogen nutrition is one of the major factors that limit growth and production of crop plants. It affects many processes, such as development, architecture, flowering, senescence and photosynthesis. Although the improvement in technologies for protein study and the widening of gene sequences have made possible the study of the plant proteomes, only limited information on proteome changes occurring in response to nitrogen amount are available up to now. In this work, two-dimensional gel electrophoresis (2-DE) has been used to investigate the protein changes induced by NO3- concentration in both roots and leaves of maize (Zea mays L.) plants. Moreover, in order to better evaluate the proteomic results, some biochemical and physiological parameters were measured. RESULTS Through 2-DE analysis, 20 and 18 spots that significantly changed their amount at least two folds in response to nitrate addition to the growth medium of starved maize plants were found in roots and leaves, respectively. Most of these spots were identified by Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS). In roots, many of these changes were referred to enzymes involved in nitrate assimilation and in metabolic pathways implicated in the balance of the energy and redox status of the cell, among which the pentose phosphate pathway. In leaves, most of the characterized proteins were related to regulation of photosynthesis. Moreover, the up-accumulation of lipoxygenase 10 indicated that the leaf response to a high availability of nitrate may also involve a modification in lipid metabolism.Finally, this proteomic approach suggested that the nutritional status of the plant may affect two different post-translational modifications of phosphoenolpyruvate carboxylase (PEPCase) consisting in monoubiquitination and phosphorylation in roots and leaves, respectively. CONCLUSION This work provides a first characterization of the proteome changes that occur in response to nitrate availability in leaves and roots of maize plants. According to previous studies, the work confirms the relationship between nitrogen and carbon metabolisms and it rises some intriguing questions, concerning the possible role of NO and lipoxygenase 10 in roots and leaves, respectively. Although further studies will be necessary, this proteomic analysis underlines the central role of post-translational events in modulating pivotal enzymes, such as PEPCase.
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Affiliation(s)
- Bhakti Prinsi
- Dipartimento di Produzione Vegetale, University of Milan, via Celoria 2, I-20133 Milano, Italy
| | - Alfredo S Negri
- Dipartimento di Produzione Vegetale, University of Milan, via Celoria 2, I-20133 Milano, Italy
| | - Paolo Pesaresi
- Dipartimento di Produzione Vegetale, University of Milan c/o Fondazione Parco Tecnologico Padano, via Einstein – Località Cascina Codazza, I-26900 Lodi, Italy
| | - Maurizio Cocucci
- Dipartimento di Produzione Vegetale, University of Milan, via Celoria 2, I-20133 Milano, Italy
| | - Luca Espen
- Dipartimento di Produzione Vegetale, University of Milan, via Celoria 2, I-20133 Milano, Italy
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Cai H, Zhou Y, Xiao J, Li X, Zhang Q, Lian X. Overexpressed glutamine synthetase gene modifies nitrogen metabolism and abiotic stress responses in rice. PLANT CELL REPORTS 2009; 28:527-37. [PMID: 19123004 DOI: 10.1007/s00299-008-0665-z] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 12/15/2008] [Accepted: 12/18/2008] [Indexed: 05/19/2023]
Abstract
Glutamine synthetase (GS; EC 6.3.1.2) is a key enzyme in nitrogen metabolism; it catalyzes the critical incorporation of inorganic ammonium into glutamine. Two full-length cDNAs that encode the rice (Oryza sativa) cytosolic glutamine synthetase1 genes (OsGS1;1 and OsGS1;2) were isolated from a Minghui 63 normalized cDNA library, and glnA encoding GS in Escherichia coli was isolated by PCR amplification. Transformants for GS gene (GS1;1, GS1;2, and glnA) in rice were produced by an Agrobacterium tumefaciens-mediated transformation method, and transcripts of GS gene accumulated at higher levels in the primary transgenic plants. Our results indicated an increased metabolic level in GS-overexpressed plants, which showed higher total GS activities and soluble protein concentrations in leaves and higher total amino acids and total nitrogen content in the whole plant. Decreases in both grain yield production and total amino acids were observed in seeds of GS-overexpressed plants compared with wild-type plants. In addition, GS1;2-overexpressed plants exhibited resistance to Basta selection and higher sensitivity to salt, drought, and cold stress conditions, whereas the other two types of GS-overexpressed plants failed to show any significant changes for these stress conditions compared with wild-type plants.
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Affiliation(s)
- Hongmei Cai
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
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Pornprom T, Prodmatee N, Chatchawankanphanich O. Glutamine synthetase mutation conferring target-site-based resistance to glufosinate in soybean cell selections. PEST MANAGEMENT SCIENCE 2009; 65:216-22. [PMID: 19097025 DOI: 10.1002/ps.1671] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Accepted: 08/04/2008] [Indexed: 05/27/2023]
Abstract
BACKGROUND Glufosinate-resistant soybean cells were achieved through direct selection of diploid cells in the suspension culture. Here, the mutations in the glutamine synthetase (GS) gene are described to understand the evidence pointing to the functional role of the GS gene in the herbicide sensitivity of the mutant cells. RESULTS Based on the I(50) values, dose-response experiments at the cell level showed that the resistance ratio of the resistant cell was 50-fold, whereas the in vitro inhibition of GS activity required a 4.56-fold greater concentration of glufosinate in the resistant cell than in the untreated control. Comparison of the nucleotide sequences identified nine point differences in the GS gene between the resistant and untreated cells, leading to eight amino acid substitutions in the deduced polypeptide sequence. Northern hybridization of the GS mRNA showed that the accumulation of GS gene mRNA transcript in resistant cells was higher than that in the untreated cells. CONCLUSION Changes in sensitivity to glufosinate have been related to mutations at the binding site of the herbicide on the glutamine synthetase. His(249) is one of the residues implicated in the binding domain for the substrate and inhibitor, and hence the exchange of this residue with tyrosine plays a role in lowering the sensitivity of the mutated enzyme.
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Affiliation(s)
- Tosapon Pornprom
- Department of Agronomy, Faculty of Agriculture, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom 73140, Thailand.
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PVAS3, a class-II ubiquitous asparagine synthetase from the common bean (Phaseolus vulgaris). Mol Biol Rep 2009; 36:2249-58. [PMID: 19130295 DOI: 10.1007/s11033-008-9441-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Accepted: 12/19/2008] [Indexed: 10/21/2022]
Abstract
A gene encoding a putative asparagine synthetase (AS; EC 6.3.5.4) has been isolated from common bean (Phaseolus vulgaris). A 2.4 kb cDNA clone of this gene (PVAS3) encodes a protein of 570 amino acids with a predicted molecular mass of 64,678 Da, an isoelectric point of 6.45, and a net charge of -5.9 at pH 7.0. The PVAS3 protein sequence conserves all the amino acid residues that are essential for glutamine-dependent AS, and PVAS3 complemented an E. coli asparagine auxotroph, that demonstrates that it encodes a glutamine-dependent AS. PVAS3 displayed significant similarity to other AS. It showed the highest similarity to soybean SAS3 (92.9% identity), rice AS (73.7% identity), Arabidopsis ASN2 (73.2%) and sunflower HAS2 (72.9%). A phylogenetic analysis revealed that PVAS3 belongs to class-II asparagine synthetases. Expression analysis by real-time RT-PCR revealed that PVAS3 is expressed ubiquitously and is not repressed by light.
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Bernard SM, Habash DZ. The importance of cytosolic glutamine synthetase in nitrogen assimilation and recycling. THE NEW PHYTOLOGIST 2009; 182:608-620. [PMID: 19422547 DOI: 10.1111/j.1469-8137.2009.02823.x] [Citation(s) in RCA: 285] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Glutamine synthetase assimilates ammonium into amino acids, thus it is a key enzyme for nitrogen metabolism. The cytosolic isoenzymes of glutamine synthetase assimilate ammonium derived from primary nitrogen uptake and from various internal nitrogen recycling pathways. In this way, cytosolic glutamine synthetase is crucial for the remobilization of protein-derived nitrogen. Cytosolic glutamine synthetase is encoded by a small family of genes that are well conserved across plant species. Members of the cytosolic glutamine synthetase gene family are regulated in response to plant nitrogen status, as well as to environmental cues, such as nitrogen availability and biotic/abiotic stresses. The complex regulation of cytosolic glutamine synthetase at the transcriptional to post-translational levels is key to the establishment of a specific physiological role for each isoenzyme. The diverse physiological roles of cytosolic glutamine synthetase isoenzymes are important in relation to current agricultural and ecological issues.
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Affiliation(s)
- Stéphanie M Bernard
- Earth Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
| | - Dimah Z Habash
- Plant Science Department, Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
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Valadier MH, Yoshida A, Grandjean O, Morin H, Kronenberger J, Boutet S, Raballand A, Hase T, Yoneyama T, Suzuki A. Implication of the glutamine synthetase/glutamate synthase pathway in conditioning the amino acid metabolism in bundle sheath and mesophyll cells of maize leaves. FEBS J 2008; 275:3193-206. [DOI: 10.1111/j.1742-4658.2008.06472.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bernard SM, Møller ALB, Dionisio G, Kichey T, Jahn TP, Dubois F, Baudo M, Lopes MS, Tercé-Laforgue T, Foyer CH, Parry MAJ, Forde BG, Araus JL, Hirel B, Schjoerring JK, Habash DZ. Gene expression, cellular localisation and function of glutamine synthetase isozymes in wheat (Triticum aestivum L.). PLANT MOLECULAR BIOLOGY 2008; 67:89-105. [PMID: 18288574 DOI: 10.1007/s11103-008-9303-y] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 01/28/2008] [Indexed: 05/25/2023]
Abstract
We present the first cloning and study of glutamine synthetase (GS) genes in wheat (Triticum aestivum L.). Based on sequence analysis, phylogenetic studies and mapping data, ten GS sequences were classified into four sub-families: GS2 (a, b and c), GS1 (a, b and c), GSr (1 and 2) and GSe (1 and 2). Phylogenetic analysis showed that the wheat GS sub-families together with the GS genes from other monocotyledonous species form four distinct clades. Immunolocalisation studies in leaves, stems and rachis in plants at flowering showed GS protein to be present in parenchyma, phloem companion and perifascicular sheath cells. In situ localisation confirmed that GS1 transcripts were present in the perifascicular sheath cells whilst those for GSr were confined to the vascular cells. Studies of the expression and protein profiles showed that all GS sub-families were differentially expressed in the leaves, peduncle, glumes and roots. Expression of GS genes in leaves was developmentally regulated, with both GS2 and GS1 assimilating or recycling ammonia in leaves during the period of grain development and filling. During leaf senescence the cytosolic isozymes, GS1 and GSr, were the predominant forms, suggesting major roles in assimilating ammonia during the critical phases of remobilisation of nitrogen to the grain. A preliminary analysis of three different wheat genotypes showed that the ratio of leaf GS2 protein to GS1 protein was variable. Use of this genetic variation should inform future efforts to modulate this enzyme for pre-breeding efforts to improve nitrogen use in wheat.
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Affiliation(s)
- Stéphanie M Bernard
- Plant Science Department, Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire, UK
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Light modulates activity and expression of glutamine synthetase isoforms in maize seedling roots. ARCH BIOL SCI 2008. [DOI: 10.2298/abs0804649s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
In maize roots, continuous illumination inhibits chloroplastic glutamine synthetase (GS2) activity, which decreased in light from 72.8% in 4-day-old to 26% in 10-day-old plants. In dark-adapted plants transferred to light for 6 days, GS2 activity declined from 100% to 41%, but in light-adapted plants transferred to darkness, it increased to the level of the dark control. Changes of cytosolic (GS1) activity were minor, with a similar trend. Quantitative RT-PCR revealed that light/dark treatments moderately affected only transcription of GS1 isoforms, with the exception of GS1-2, which was dramatically induced by darkness and repressed by light.
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Simonović AD, Anderson MD. Analysis of methionine oxides and nitrogen-transporting amino acids in chilled and acclimated maize seedlings. Amino Acids 2007; 33:607-13. [PMID: 17334901 DOI: 10.1007/s00726-007-0503-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 01/22/2007] [Indexed: 11/25/2022]
Abstract
In maize seedlings, chilling causes a reduction of glutamine synthetase (GS) activity, while acclimation protects GS (manuscript submitted). Since ROS can oxidize both protein-bound and free Met to methionine sulfoxide (MSO) and further to methionine sulfone (MSO2, a GS inhibitor), it was hypothesized that the chilling-induced oxidative stress may cause accumulation of MSO and MSO2, thus contributing to the inactivation of GS. MSO2 preferentially inhibited the chloroplastic isoform, GS2. HPLC analysis of polar amino acids from coleoptiles + leaves, mesocotyls and roots of control, chilled, acclimated, acclimated and chilled and chilled and rewarmed plants revealed that free MSO and MSO2 do not accumulate after low temperature treatments. Nevertheless, acclimation significantly increased the expression of putative protein methionine sulfoxide reductase (PMSR), especially in mesocotyls. Different low temperature treatments caused complex changes in the profiles of N-transporting amino acids, Asp, Glu, Asn and Gln.
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Affiliation(s)
- A D Simonović
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA.
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39
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Effect of chilling and acclimation on the activity of glutamine synthetase isoforms in maize seedlings. ARCH BIOL SCI 2007. [DOI: 10.2298/abs0703177s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Effects of chilling and acclimation on the activity of cytosolic (GS1) and plastidic (GS2) isoforms of glutamine synthetase (E.C. 6.3.1.2) were studied in chilling-sensitive and acclimation-responsive maize inbred G50. Glutamine synthetase activity in mesocotyls and roots of chilled (7 d/4?C) and rewarmed (1 d/27?C) etiolated plants was "1/3 that of controls. In coleoptiles+leaves of light-grown plants, GS1 was reduced to 75%, and GS2 to 50%. Acclimation (3 d/14?C) increased GS activity and alleviated the effects of chilling. Exposure to H2O2 or menadione also reduced GS activity. Since chilling causes oxidative stress in maize, acclimation probably preserves GS activity by protecting GS from oxidative inactivation. .
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Martin A, Lee J, Kichey T, Gerentes D, Zivy M, Tatout C, Dubois F, Balliau T, Valot B, Davanture M, Tercé-Laforgue T, Quilleré I, Coque M, Gallais A, Gonzalez-Moro MB, Bethencourt L, Habash DZ, Lea PJ, Charcosset A, Perez P, Murigneux A, Sakakibara H, Edwards KJ, Hirel B. Two cytosolic glutamine synthetase isoforms of maize are specifically involved in the control of grain production. THE PLANT CELL 2006; 18:3252-74. [PMID: 17138698 PMCID: PMC1693956 DOI: 10.1105/tpc.106.042689] [Citation(s) in RCA: 284] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The roles of two cytosolic maize glutamine synthetase isoenzymes (GS1), products of the Gln1-3 and Gln1-4 genes, were investigated by examining the impact of knockout mutations on kernel yield. In the gln1-3 and gln1-4 single mutants and the gln1-3 gln1-4 double mutant, GS mRNA expression was impaired, resulting in reduced GS1 protein and activity. The gln1-4 phenotype displayed reduced kernel size and gln1-3 reduced kernel number, with both phenotypes displayed in gln1-3 gln1-4. However, at maturity, shoot biomass production was not modified in either the single mutants or double mutants, suggesting a specific impact on grain production in both mutants. Asn increased in the leaves of the mutants during grain filling, indicating that it probably accumulates to circumvent ammonium buildup resulting from lower GS1 activity. Phloem sap analysis revealed that unlike Gln, Asn is not efficiently transported to developing kernels, apparently causing reduced kernel production. When Gln1-3 was overexpressed constitutively in leaves, kernel number increased by 30%, providing further evidence that GS1-3 plays a major role in kernel yield. Cytoimmunochemistry and in situ hybridization revealed that GS1-3 is present in mesophyll cells, whereas GS1-4 is specifically localized in the bundle sheath cells. The two GS1 isoenzymes play nonredundant roles with respect to their tissue-specific localization.
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Affiliation(s)
- Antoine Martin
- Unité de Nutrition Azotée des Plantes UR511, Institut National de la Recherche Agronomique, F-78026 Versailles Cedex, France
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41
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Lima L, Seabra A, Melo P, Cullimore J, Carvalho H. Phosphorylation and subsequent interaction with 14-3-3 proteins regulate plastid glutamine synthetase in Medicago truncatula. PLANTA 2006; 223:558-67. [PMID: 16136328 DOI: 10.1007/s00425-005-0097-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Accepted: 07/13/2005] [Indexed: 05/04/2023]
Abstract
In this report we demonstrate that plastid glutamine synthetase of Medicago truncatula (MtGS2) is regulated by phosphorylation and 14-3-3 interaction. To investigate regulatory aspects of GS2 phosphorylation, we have produced non-phosphorylated GS2 proteins by expressing the plant cDNA in E. coli and performed in vitro phosphorylation assays. The recombinant isoenzyme was phosphorylated by calcium dependent kinase(s) present in leaves, roots and nodules. Using an (His)6-tagged 14-3-3 protein column affinity purification method, we demonstrate that phosphorylated GS2 interacts with 14-3-3 proteins and that this interaction leads to selective proteolysis of the plastid located isoform, resulting in inactivation of the isoenzyme. By site directed mutagenesis we were able to identify a GS2 phosphorylation site (Ser97) crucial for the interaction with 14-3-3s. Phosphorylation of this target residue can be functionally mimicked by replacing Ser97 by Asp, indicating that the introduction of a negative charge contributes to the interaction with 14-3-3 proteins and subsequent specific proteolysis. Furthermore, we document that plant extracts contain protease activity that cleaves the GS2 protein only when it is bound to 14-3-3 proteins following either phosphorylation or mimicking of phosphorylation by Ser97Asp.
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Affiliation(s)
- Lígia Lima
- Instituto de Biologia Molecular e Celular Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
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Martin A, Belastegui-Macadam X, Quilleré I, Floriot M, Valadier MH, Pommel B, Andrieu B, Donnison I, Hirel B. Nitrogen management and senescence in two maize hybrids differing in the persistence of leaf greenness: agronomic, physiological and molecular aspects. THE NEW PHYTOLOGIST 2005; 167:483-92. [PMID: 15998400 DOI: 10.1111/j.1469-8137.2005.01430.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Here, nitrogen management within the plant was compared in an early-senescing maize hybrid and in a late-senescing maize hybrid, both grown under field conditions with a high fertilisation input involving large quantities of fertiliser. We monitored, in representative leaf stages, the changes in metabolite content, enzyme activities and steady-state levels of transcripts for marker genes of N primary assimilation, N recycling and leaf senescence. The hybrids differed in terms of persistence of leaf greenness, the expression of marker genes and the concentration of enzymes used to describe the transition from N assimilation to N recycling. The transcription of leaf-senescence marker genes did not differ. Agronomic studies confirmed the ability of the late-senescing hybrid to absorb and store more N in shoots. Despite the differences in the mode of N management adopted by the two hybrids, we conclude that leaf senescence occurs independently of the source-to-sink transition at the high level of fertilisation used involving large quantities of fertiliser. The possibility of improving N metabolic efficiency in the latest maize hybrids is discussed.
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Affiliation(s)
- Antoine Martin
- Unité de Nutrition Azotée des plantes, INRA, R.D. 10, 78026 Versailles Cedex, France
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Man HM, Boriel R, El-Khatib R, Kirby EG. Characterization of transgenic poplar with ectopic expression of pine cytosolic glutamine synthetase under conditions of varying nitrogen availability. THE NEW PHYTOLOGIST 2005; 167:31-9. [PMID: 15948827 DOI: 10.1111/j.1469-8137.2005.01461.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The present study addresses the hypothesis that enhanced expression of glutamine synthetase (GS) in transgenic poplar, characterized by the ectopic expression of pine cytosolic GS, results in an enhanced efficiency of nitrogen (N) assimilation and enhanced growth. Transgenic and control poplar were supplied with low and high N levels and the role of ectopic expression of the pine GS in growth and N assimilation was assessed by using amino acid analysis, (15)N enrichment, biochemical analyses, and growth measurements. While leaves of transgenic poplar contained 85% less (P < 0.01) free ammonium than leaves of nontransgenic control plants, leaves of transgenics showed increases in the levels of free glutamine and total free amino acids. Transgenic poplar lines also displayed significant increases in growth parameters when compared with controls grown under both low (0.3 mm) and high (10 mm) nitrate conditions. Furthermore, (15)N-enrichment experiments showed that 27% more (P < 0.05) (15)N was incorporated into structural compounds in transgenic lines than in nontransgenic controls. Using the methods described here, we present direct evidence for increased N assimilation efficiency and growth in GS transgenic lines.
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Affiliation(s)
- Hui-Min Man
- Department of Biological Sciences, Rutgers University, University Heights, Newark, NJ 07102, USA
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Ishiyama K, Inoue E, Watanabe-Takahashi A, Obara M, Yamaya T, Takahashi H. Kinetic properties and ammonium-dependent regulation of cytosolic isoenzymes of glutamine synthetase in Arabidopsis. J Biol Chem 2004; 279:16598-605. [PMID: 14757761 DOI: 10.1074/jbc.m313710200] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glutamine synthetase (GS; EC 6.3.1.2) is a key enzyme of nitrogen assimilation, catalyzing the synthesis of glutamine from ammonium and glutamate. In Arabidopsis, cytosolic GS (GS1) was accumulated in roots when plants were excessively supplied with ammonium; however, the GS activity was controlled at a constant level. The discrepancy between the protein content and enzyme activity of GS1 was attributable to the kinetic properties and expression of four distinct isoenzymes encoded by GLN1;1, GLN1;2, GLN1;3 and GLN1;4, genes that function complementary to each other in Arabidopsis roots. GLN1;2 was the only isoenzyme significantly up-regulated by ammonium, which correlated with the rapid increase in total GS1 protein. GLN1;2 was localized in the vasculature and exhibited low affinities to ammonium (Km = 2450 +/- 150 microm) and glutamate (Km = 3.8 +/- 0.2 mm). The expression of the counterpart vascular tissue-localizing low affinity isoenzyme, GLN1;3, was not stimulated by ammonium; however, the enzyme activity of GLN1;3 was significantly inhibited by a high concentration of glutamate. By contrast, the high affinity isoenzyme, GLN1;1 (Km for ammonium < 10 microm; Km for glutamate = 1.1 +/- 0.4 mm) was abundantly accumulated in the surface layers of roots during nitrogen limitation and was down-regulated by ammonium excess. GLN1;4 was another high affinity-type GS1 expressed in nitrogen-starved plants but was 10-fold less abundant than GLN1;1. These results suggested that dynamic regulations of high and low affinity GS1 isoenzymes at the levels of mRNA and enzyme activities are dependent on nitrogen availabilities and may contribute to the homeostatic control of glutamine synthesis in Arabidopsis roots.
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Affiliation(s)
- Keiki Ishiyama
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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45
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Gallais A, Hirel B. An approach to the genetics of nitrogen use efficiency in maize. JOURNAL OF EXPERIMENTAL BOTANY 2004; 55:295-306. [PMID: 14739258 DOI: 10.1093/jxb/erh006] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
To study the genetic variability and the genetic basis of nitrogen (N) use efficiency in maize, a set of recombinant inbred lines crossed with a tester was studied at low input (N-) and high input (N+) for grain yield and its components, grain protein content, and post-anthesis nitrogen uptake and remobilization. Other physiological traits, such as nitrate content, nitrate reductase, glutamine synthetase (GS), and glutamate dehydrogenase activities were studied at the level of the lines. Genotypexnitrogen (GxN) interaction was significant for yield and explained by variation in kernel number. In N-, N-uptake, the nitrogen nutrition index, and GS activity in the vegetative stage were positively correlated with grain yield, whereas leaf senescence was negatively correlated. Whatever N-input, post-anthesis N-uptake was highly negatively related to N-remobilization. As a whole, genetic variability was expressed differently in N+ and N-. This was confirmed by the detection of QTLs. More QTLs were detected in N+ than in N- for traits of vegetative development, N-uptake, and grain yield and its components, whereas it was the reverse for grain protein content and N-utilization efficiency. Several coincidences between genes encoding for enzymes of N metabolism and QTLs for the traits studied were observed. In particular, coincidences in three chromosome regions of QTLs for yield and N-remobilization, QTLs for GS activity and a gene encoding cytosolic GS were observed. This may have a physiological meaning. The GS locus on chromosome 5 appears to be a good candidate gene which can, at least partially, explain the variation in nitrogen use efficiency.
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Affiliation(s)
- A Gallais
- Station de Génétique Végétale, INRA-UPS-INAPG, Ferme du Moulon, 91190 Gif/Yvette, France.
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Carvalho HG, Lopes-Cardoso IA, Lima LM, Melo PM, Cullimore JV. Nodule-specific modulation of glutamine synthetase in transgenic Medicago truncatula leads to inverse alterations in asparagine synthetase expression. PLANT PHYSIOLOGY 2003; 133:243-52. [PMID: 12970490 PMCID: PMC196601 DOI: 10.1104/pp.102.017830] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2002] [Revised: 02/17/2003] [Accepted: 05/07/2003] [Indexed: 05/18/2023]
Abstract
Transgenic Medicago truncatula plants were produced harboring chimeric gene constructs of the glutamine synthetase (GS) cDNA clones (MtGS1a or MtGS1b) fused in sense or antisense orientation to the nodule-specific leghemoglobin promoter Mtlb1. A series of transgenic plants were obtained showing a 2- to 4-fold alteration in nodule GS activity when compared with control plants. Western and northern analyses revealed that the increased or decreased levels of GS activity correlate with the amount of cytosolic GS polypeptides and transcripts present in the nodule extracts. An analysis of the isoenzyme composition showed that the increased or decreased levels of GS activity were attributable to major changes in the homo-octameric isoenzyme GS1a. Nodules of plants transformed with antisense GS constructs showed an increase in the levels of both asparagine synthetase (AS) polypeptides and transcripts when compared with untransformed control plants, whereas the sense GS transformants showed decreased AS transcript levels but polypeptide levels similar to control plants. The polypeptide abundance of other nitrogen metabolic enzymes NADH-glutamic acid synthase and aspartic acid amino-transferase as well as those of major carbon metabolic enzymes phosphoenolpyruvate carboxylase, carbonic anhydrase, and sucrose synthase were not affected by the GS-gene manipulations. Increased levels of AS polypeptides and transcripts were also transiently observed in nodules by inhibiting GS activity with phosphinothricin. Taken together, the results presented here suggest that GS activity negatively regulates the level of AS in root nodules of M. truncatula. The potential role of AS in assimilating ammonium when GS becomes limiting is discussed.
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Affiliation(s)
- Helena G Carvalho
- Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
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47
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Muhitch MJ. Distribution of the glutamine synthetase isozyme GSp1 in maize (Zea mays). JOURNAL OF PLANT PHYSIOLOGY 2003; 160:601-605. [PMID: 12872481 DOI: 10.1078/0176-1617-01046] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In maize (Zea mays L.), GSp1, the predominant GS isozyme of the developing kernel, is abundant in the pedicel and pericarp, but absent from the endosperm and embryo. Determinations of GSp1 tissue distribution in vegetative tissues have been limited thus far to root and leaves, where the isozyme is absent. However, the promoter from the gene encoding GSp1 has been shown to drive reporter gene expression not only in the maternal seed-associated tissues in transgenic maize plants, but also in the anthers, husks and pollen (Muhitch et al. 2002, Plant Sci 163: 865-872). Here we report chromatographic evidence that GSp1 resides in immature tassels, dehiscing anthers, kernel glumes, ear husks, cobs and stalks of maize plants, but not in mature, shedding pollen grains. RNA blot analysis confirmed these biochemical data. In stalks, GSp1 increased in the later stages of ear development, suggesting that it plays a role in nitrogen remobilization during grain fill.
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Affiliation(s)
- Michael J Muhitch
- Mycotoxin Research Unit, National Center for Agricultural Utilization Research, ARS/USDA, 1815 N. University St., Peoria, IL 61604, USA.
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48
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Herrera-Rodríguez MB, Carrasco-Ballesteros S, Maldonado JM, Pineda M, Aguilar M, Pérez-Vicente R. Three genes showing distinct regulatory patterns encode the asparagine synthetase of sunflower (Helianthus annuus). THE NEW PHYTOLOGIST 2002; 155:33-45. [PMID: 33873300 DOI: 10.1046/j.1469-8137.2002.00437.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
• Asparagine metabolism in sunflower (Helianthus annuus) was investigated by cDNA cloning, sequence characterization and expression analysis of three genes encoding different isoforms of asparagine synthetase (AS, EC 6.3.5.4). • The AS-coding sequences were searched for in leaves, roots and cotyledons by using a methodology based on the simultaneous amplification of different cDNAs. Three distinct AS-coding genes, HAS1, HAS1.1 and HAS2, were identified. • HAS1 and HAS1.1 are twin genes with closely related sequences that share some regulatory features. By contrast, HAS2 is a singular sequence that encodes an incomplete AS polypeptide and shows an unusual regulation. The functionality of both the complete HAS1 and the truncated HAS2 proteins was demonstrated by complementation assays. Northern analysis revealed that HAS1, HAS1.1 and HAS2 were differentially regulated dependent on the organ, the physiological status, the developmental stage and the light conditions. • Asparagine synthetase from sunflower is encoded by a small gene family whose members have achieved a significant degree of specialization to cope with the major situations requiring asparagine synthesis.
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Affiliation(s)
- María Begoña Herrera-Rodríguez
- Departamento de Biología Vegetal, División de Fisiología Vegetal, Universidad de Córdoba, Avda. San Alberto Magno s/n, E-14071 Córdoba, Spain
| | - Susana Carrasco-Ballesteros
- Departamento de Biología Vegetal, División de Fisiología Vegetal, Universidad de Córdoba, Avda. San Alberto Magno s/n, E-14071 Córdoba, Spain
| | - José María Maldonado
- Departamento de Fisiología Vegetal y Ecología, Unidad de Fisiología Vegetal, Facultad de Biología, Universidad de Sevilla, Avda, Reina Mercedes 6, E-41012 Seville, Spain
| | - Manuel Pineda
- Departamento de Bioquímica y Biología Molecular. Universidad de Córdoba, Campus Rabanales, Edif. C-6, 1a Planta, E-14071 Córdoba, Spain
| | - Miguel Aguilar
- Departamento de Bioquímica y Biología Molecular. Universidad de Córdoba, Campus Rabanales, Edif. C-6, 1a Planta, E-14071 Córdoba, Spain
| | - Rafael Pérez-Vicente
- Departamento de Biología Vegetal, División de Fisiología Vegetal, Universidad de Córdoba, Avda. San Alberto Magno s/n, E-14071 Córdoba, Spain
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Oliveira IC, Brears T, Knight TJ, Clark A, Coruzzi GM. Overexpression of cytosolic glutamine synthetase. Relation to nitrogen, light, and photorespiration. PLANT PHYSIOLOGY 2002; 129:1170-80. [PMID: 12114571 PMCID: PMC166511 DOI: 10.1104/pp.020013] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2002] [Accepted: 04/10/2002] [Indexed: 05/18/2023]
Abstract
In plants, ammonium released during photorespiration exceeds primary nitrogen assimilation by as much as 10-fold. Analysis of photorespiratory mutants indicates that photorespiratory ammonium released in mitochondria is reassimilated in the chloroplast by a chloroplastic isoenzyme of glutamine synthetase (GS2), the predominant GS isoform in leaves of Solanaceous species including tobacco (Nicotiana tabacum). By contrast, cytosolic GS1 is expressed in the vasculature of several species including tobacco. Here, we report the effects on growth and photorespiration of overexpressing a cytosolic GS1 isoenzyme in leaf mesophyll cells of tobacco. The plants, which ectopically overexpress cytosolic GS1 in leaves, display a light-dependent improved growth phenotype under nitrogen-limiting and nitrogen-non-limiting conditions. Improved growth was evidenced by increases in fresh weight, dry weight, and leaf soluble protein. Because the improved growth phenotype was dependent on light, this suggested that the ectopic expression of cytosolic GS1 in leaves may act via photosynthetic/photorespiratory process. The ectopic overexpression of cytosolic GS1 in tobacco leaves resulted in a 6- to 7-fold decrease in levels of free ammonium in leaves. Thus, the overexpression of cytosolic GS1 in leaf mesophyll cells seems to provide an alternate route to chloroplastic GS2 for the assimilation of photorespiratory ammonium. The cytosolic GS1 transgenic plants also exhibit an increase in the CO(2) photorespiratory burst and an increase in levels of photorespiratory intermediates, suggesting changes in photorespiration. Because the GS1 transgenic plants have an unaltered CO(2) compensation point, this may reflect an accompanying increase in photosynthetic capacity. Together, these results provide new insights into the possible mechanisms responsible for the improved growth phenotype of cytosolic GS1 overexpressing plants. Our studies provide further support for the notion that the ectopic overexpression of genes for cytosolic GS1 can potentially be used to affect increases in nitrogen use efficiency in transgenic crop plants.
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50
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Miflin BJ, Habash DZ. The role of glutamine synthetase and glutamate dehydrogenase in nitrogen assimilation and possibilities for improvement in the nitrogen utilization of crops. JOURNAL OF EXPERIMENTAL BOTANY 2002; 53:979-87. [PMID: 11912240 DOI: 10.1093/jexbot/53.370.979] [Citation(s) in RCA: 346] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
This short review outlines the central role of glutamine synthetase (GS) in plant nitrogen metabolism and discusses some possibilities for crop improvement. GS functions as the major assimilatory enzyme for ammonia produced from N fixation, and nitrate or ammonia nutrition. It also reassimilates ammonia released as a result of photorespiration and the breakdown of proteins and nitrogen transport compounds. GS is distributed in different subcellular locations (chloroplast and cytoplasm) and in different tissues and organs. This distribution probably changes as a function of the development of the tissue, for example, GS1 appears to play a key role in leaf senescence. The enzyme is the product of multiple genes with complex promoters that ensure the expression of the genes in an organ- and tissue-specific manner and in response to a number of environmental variables affecting the nutritional status of the cell. GS activity is also regulated post-translationally in a manner that involves 14-3-3 proteins and phosphorylation. GS and plant nitrogen metabolism is best viewed as a complex matrix continually changing during the development cycle of plants. Along with GS, a number of other enzymes play key roles in maintaining the balance of carbon and nitrogen. It is proposed that one of these is glutamate dehydrogenase (GDH). There is considerable evidence for a GDH shunt to return the carbon in amino acids back into reactions of carbon metabolism and the tri-carboxylic acid cycle. Results with transgenic plants containing transferred GS genes suggest that there may be ways in which it is possible to improve the efficiency with which crop plants use nitrogen. Marker-assisted breeding may also bring about such improvements.
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Affiliation(s)
- Ben J Miflin
- Crop Performance and Improvement Division, IACR-Rothamsted, Harpenden, Hertfordshire AL5 2JQ, UK.
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